Two of the biggest challenges in developing next generation packaging technologies are package warpage reduction and package thickness reduction. These challenges are due to the ever increasing demand in the consumer microelectronic market for smaller and thinner devices.
In many conventional electronic packages an over-mold is used to try to control temperature-related warpage of electronic packages. There are several drawbacks that are associated with conventional over-mold electronic packaging solutions. These drawbacks are due to manufacturing considerations associated with using (i) relatively high temperatures during fabrication of the electronic packages; and (ii) smaller form factors for the electronic packages.
Electronic packages may differ in size and/or form factor. One of the drawbacks with conventional electronic packages relates to finding a proper mold material for different types of electronic packages. One important consideration when over-molding is balancing the electronic component(s) that form the electronic package with the over-mold.
As an example, a die area of the electronic package may have a very different stiffness and thermal expansion coefficient than a non-die area. Therefore, when the electronic package geometry changes, the over-mold material and over-mold thickness may need to be reconfigured.
There is no universal over-mold solution for different types of electronic packages. The overlying mold that is typically used in electronic packages often cracks due to excessive mechanical stresses (especially in the edge regions of the mold). Changing over-mold materials for each type of electronic package does not promote efficient manufacturing of electronic packages.
Many conventional electronic packages typically include a separate solid stiffener that is mounted to the back side of a die using an adhesive. One of the drawbacks with using such a stiffener is that there is often failure due to delamination between the adhesive and the stiffener.